Wall St slips as bank, health stocks drag

US stocks have opened slightly lower, weighed down by losses in bank and healthcare stocks.

Oil prices on Wednesday fell 0.5 per cent as an increase in US crude inventories and a slump in Chinese demand implied that global oil markets remain oversupplied despite OPEC-led efforts to cut output.

The S&P 500 financial index, which has outperformed other sectors in a post-election rally, was down 0.83 per cent and was on track for its third straight day of decline.

Healthcare was off 0.66 per cent, dragged down by Gilead.

The drugmaker's stock, which also weighed on the S&P and the Nasdaq, was down 9.3 per cent after the company projected disappointing sales for its hepatitis C drugs this year.

However, the fourth-quarter earnings season is expected to end on a high note. Combined earnings of S&P 500 companies are estimated to have risen 8.2 per cent - the most in nine quarters.

In early tradem the Dow Jones Industrial Average was down 40.95 points, or 0.2 per cent, at 20,049.34, the S&P 500 was down 5.31 points, or 0.23 per cent, at 2,287.77 and the Nasdaq Composite was down 17.04 points, or 0.3 per cent, at 5,657.18.

Walt Disney was up 1.6 per cent at $US110.89 after Bob Iger said he was open to extending his term as chief executive officer.

Cognizant rose four per cent to $US55.96 after the IT services provider named three directors to its board and announced a $US3.4 billion ($A4.5 billion) share buyback program, bowing to pressure from activist shareholder Elliott Management.

US carrier Alaska Air rose 2.5 per cent to $US96.23 after the company reported a 10.7 per cent jump in quarterly revenue.

Declining issues outnumbered advancers on the NYSE by 1684 to 946. On the Nasdaq, 1657 issues fell and 698 advanced.

The S&P 500 index showed six new 52-week highs and three new lows, while the Nasdaq recorded 26 new highs and 18 new lows.